From: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>
To: "christophe.leroy@c-s.fr" <christophe.leroy@c-s.fr>,
"linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>
Subject: Re: hardcoded SIGSEGV in __die() ?
Date: Mon, 23 Mar 2020 15:44:55 +0000 [thread overview]
Message-ID: <6b3484a7bf0f760570fbe7c8b22c36a244c19ff6.camel@infinera.com> (raw)
In-Reply-To: <43a21b20-4214-1043-0919-1bd8078d14a6@c-s.fr>
On Mon, 2020-03-23 at 16:31 +0100, Christophe Leroy wrote:
>
> Le 23/03/2020 à 16:08, Joakim Tjernlund a écrit :
> > On Mon, 2020-03-23 at 15:45 +0100, Christophe Leroy wrote:
> > > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
> > >
> > >
> > > Le 23/03/2020 à 15:43, Christophe Leroy a écrit :
> > > > Le 23/03/2020 à 15:17, Joakim Tjernlund a écrit :
> > > > > In __die(), see below, there is this call to notify_send() with
> > > > > SIGSEGV hardcoded, this seems odd
> > > > > to me as the variable "err" holds the true signal(in my case SIGBUS)
> > > > > Should not SIGSEGV be replaced with the true signal no.?
> > > >
> > > > As far as I can see, comes from
> > > > https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Fcommit%2F%3Fid%3D66fcb1059&data=02%7C01%7CJoakim.Tjernlund%40infinera.com%7Cefe6d37a85e1494658ec08d7cf3f513f%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C0%7C637205743206770599&sdata=k8%2Bs7ifiCyuNzXuOhykjXUEtWzD62q3HGIIiavqE6%2FA%3D&reserved=0
> > > >
> > >
> > > And
> > > https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Fcommit%2F%3Fid%3Dae87221d3ce49d9de1e43756da834fd0bf05a2ad&data=02%7C01%7CJoakim.Tjernlund%40infinera.com%7Cefe6d37a85e1494658ec08d7cf3f513f%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C0%7C637205743206770599&sdata=oCU%2FMelrWDOCjmGOfVuNp2tM%2BwQ%2BRD25jzRWoGbHAew%3D&reserved=0
> > > shows it is (was?) similar on x86.
> > >
> >
> > I tried to follow that chain thinking it would end up sending a signal to user space but I cannot see
> > that happens. Seems to be related to debugging.
> >
> > In short, I cannot see any signal being delivered to user space. If so that would explain why
> > our user space process never dies.
> > Is there a signal hidden in machine_check handler for SIGBUS I cannot see?
> >
>
> Isn't it done in do_exit(), called from oops_end() ?
hmm, so it seems. The odd thing though is that do_exit takes an exit code, not signal number.
Also, feels a bit odd to force an exit(that we haven't seen happening) rather than just a signal.
Jocke
next prev parent reply other threads:[~2020-03-23 15:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 14:17 hardcoded SIGSEGV in __die() ? Joakim Tjernlund
2020-03-23 14:43 ` Christophe Leroy
2020-03-23 14:45 ` Christophe Leroy
2020-03-23 15:08 ` Joakim Tjernlund
2020-03-23 15:31 ` Christophe Leroy
2020-03-23 15:44 ` Joakim Tjernlund [this message]
2020-03-25 17:02 ` David Laight
2020-03-25 17:09 ` Joakim Tjernlund
2020-03-26 0:28 ` Michael Ellerman
2020-03-27 10:10 ` Joakim Tjernlund
2020-03-30 17:16 ` Joakim Tjernlund
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